Presbyopia is a human condition whereby a person's eyes lose their ability to accommodate varying distances. A person with presbyopia may wear glasses or contact lenses that are optimized for distance but will have difficulties reading a book without additional accommodation. Presbyopia generally begins to occur when a person reaches an age of 40 years and progresses over time.
One solution to presbyopia is to have prescribed reading glasses. During an eye test a person may receive one set of glasses for distance vision and driving and another set for reading. To add convenience bifocal lenses can be used that provide the functionality of both types of glasses. However, there are limits to these solutions when varying reading distances are considered.
For example a person will tend to have different reading distances between different devices and situations that may include reading a laptop computer display versus reading a book while in a chair. A person of advanced age may have great difficulties reading outside of a very narrow range of distances for a given set of reading glasses or bifocals.
Another challenge is viewing displays and other objects at intermediate distances. Yet other challenges include a tendency for a user's need for a focal correction versus distance to vary with time of day or over longer time periods. What is needed is a system that facilitates visual accommodation for a range of short and intermediate viewing distances in a way that is convenient to the user.